In Greek mythology, Callisto was one of many human women who were seduced or raped by Zeus*. Daughter of the king of Arcadia, Callisto joined the followers of the goddess Artemis*. As a member of this group, Callisto swore to remain a virgin. But Zeus was tempted by Callisto—whose name meant "most beautiful"—and tricked her into lovemaking.
chastity purity or virginity
After her encounter with Zeus, the unfortunate Callisto was turned into a bear by Zeus, his wife (Hera), or Artemis as punishment for breaking her vow of chastity. Still, Callisto bore Zeus a son named Arcas, whom Zeus protected. One version of Callisto's story says that Artemis shot the bear while hunting. Another says that Callisto was shot by her own son. Feeling sorry for her, Zeus placed Callisto in the heavens, where she became the constellation known as Ursa Major, the Great Bear.